Make tree serialization more robust and add more unit tests.

ui/accessibility/ax_tree_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/scoped_ptr.h"
+#include "base/strings/string_number_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/accessibility/ax_node.h"
 #include "ui/accessibility/ax_serializable_tree.h"
 #include "ui/accessibility/ax_tree.h"
 #include "ui/accessibility/ax_tree_serializer.h"
 
 namespace ui {
 
-TEST(AXTreeTest, TestSerialize) {
+TEST(AXTreeTest, SerializeSimpleAXTree) {
   AXNodeData root;
   root.id = 1;
   root.role = AX_ROLE_ROOT_WEB_AREA;
   root.child_ids.push_back(2);
   root.child_ids.push_back(3);
 
   AXNodeData button;
   button.id = 2;
   button.role = AX_ROLE_BUTTON;
   button.state = 0;
@@ skipping 26 matching lines @@
 
   AXNode* button_node = root_node->ChildAtIndex(0);
   EXPECT_EQ(button.id, button_node->id());
   EXPECT_EQ(button.role, button_node->data().role);
 
   AXNode* checkbox_node = root_node->ChildAtIndex(1);
   EXPECT_EQ(checkbox.id, checkbox_node->id());
   EXPECT_EQ(checkbox.role, checkbox_node->data().role);
 }
 
+TEST(AXTreeTest, DeleteUnknownSubtreeFails) {
+  AXNodeData root;
+  root.id = 1;
+  root.role = AX_ROLE_ROOT_WEB_AREA;
+
+  AXTreeUpdate initial_state;
+  initial_state.nodes.push_back(root);
+  AXTree tree(initial_state);
+
+  // This should fail because we're asking it to delete
+  // a subtree rooted at id=2, which doesn't exist.
+  AXTreeUpdate update;
+  update.node_id_to_clear = 2;
+  update.nodes.resize(1);
+  update.nodes[0].id = 1;
+  update.nodes[0].id = AX_ROLE_ROOT_WEB_AREA;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Bad node_id_to_clear: 2", tree.error());
+}
+
+TEST(AXTreeTest, LeaveOrphanedDeletedSubtreeFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(3);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  initial_state.nodes[0].child_ids.push_back(2);
+  initial_state.nodes[0].child_ids.push_back(3);
+  initial_state.nodes[1].id = 2;
+  initial_state.nodes[2].id = 3;
+  AXTree tree(initial_state);
+
+  // This should fail because we delete a subtree rooted at id=2
+  // but never update it.
+  AXTreeUpdate update;
+  update.node_id_to_clear = 2;
+  update.nodes.resize(1);
+  update.nodes[0].id = 3;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Nodes left pending by the update: 2", tree.error());
+}
+
+TEST(AXTreeTest, LeaveOrphanedNewChildFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(1);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  AXTree tree(initial_state);
+
+  // This should fail because we add a new child to the root node
+  // but never update it.
+  AXTreeUpdate update;
+  update.nodes.resize(1);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(2);
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Nodes left pending by the update: 2", tree.error());
+}
+
+TEST(AXTreeTest, DuplicateChildIdFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(1);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  AXTree tree(initial_state);
+
+  // This should fail because a child id appears twice.
+  AXTreeUpdate update;
+  update.nodes.resize(2);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[1].id = 2;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Node 1 has duplicate child id 2", tree.error());
+}
+
+TEST(AXTreeTest, InvalidReparentingFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(3);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  initial_state.nodes[0].child_ids.push_back(2);
+  initial_state.nodes[1].id = 2;
+  initial_state.nodes[1].child_ids.push_back(3);
+  initial_state.nodes[2].id = 3;
+
+  AXTree tree(initial_state);
+
+  // This should fail because node 3 is reparented from node 2 to node 1
+  // without deleting node 1's subtree first.
+  AXTreeUpdate update;
+  update.nodes.resize(3);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(3);
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[1].id = 2;
+  update.nodes[2].id = 3;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Node 3 reparented from 2 to 1", tree.error());
+}
+
 }  // namespace ui